This invention relates generally to non-impact printing apparatus and more particularly to non-impact printing apparatus suitable for use in typewriters and word processing systems.
Present day typewriters and word processing systems which print by the ballistic impact of type bearing members against an inked ribbon and the paper being printed upon have inherent speed limitations caused by the necessity of mechanically actuating the type bearing members to strike the paper and ink carrying ribbon. The mechanical complexity of the machine result in a reliability lower than than which could be obtained in an electronic system and the speed obtainable, while acceptable for use with a human typist, is too low for an efficient operation when the machine is being driven by an electronic input such as a computer. The ballistic impact typewriter is also an inherently noisy machine and, especially in word processing applications, produces noise levels which are almost intolerable in confined areas.
Non-impact printing systems have not been suitable for applications in the typewriter or word processing area since they generally either require coated paper, print matrix type characters, require a very expensive printing mechanism, do not permit character by character visibility and/or generate a print quality which is too low for these applications.